A driver (e.g., an LED driver) is often used to provide power to the light sources of a lighting device. In some applications, a dimmer may be used to control the power that is provided by the driver to a light source to control the intensity of light emitted by a light source. For example, a phase-cut dimmer may be used to control the dim level of light emitted by a light source (e.g., LEDs). However, because of variations in operating ranges of phase-cut dimmers, the range of intensity levels of light emitted by a light source may be different from one dimmer to another.
To illustrate, phase-cut dimmers perform dimming operations by passing a portion of the power from a power source to a light source or to a driver that is attached to a light source depending on a dim level setting. In general, phase-cut dimmers conduct a portion of each half cycle of the power signal (e.g., mains power signal) based on the dim level setting. To illustrate, a phase-cut dimmer may pass a small percentage of the power (e.g., mains power) when the dimmer is set to a dimmest setting (e.g., slider of the dimmer is at lowest level) and may pass a relatively large percentage of the power from the power source when the dimmer is set to a brightest setting (e.g., slider is at highest level). The dim level of light from a light source that is controlled by a dimmer corresponds to the conduction duration of the electrical signal that is passed to a driver or to the light source.
The conduction duration of an electrical signal provided by a dimmer is associated with maximum and minimum firing angles of the dimmer. Because the firing angles of phase-cut dimmers vary significantly from one manufacturer to another, lighting systems that are otherwise similar may behave differently based on the maximum and minimum conduction durations of the dimmers that are used with the systems. If a driver is configured to provide a lowest and highest output power to a light source based on minimum and maximum conduction durations of an electrical signal from a particular dimmer, the driver may not provide the same lowest and highest output power when coupled to a different phase-cut dimmer.
Thus, a solution that allows the driver to learn the maximum and minimum dimming capability of a dimmer that is attached to the driver is desirable.